Address: The Terrace, Wellington
Scope of testing: Two tension tests, one compression test
Eleven micropiles (three of them were tested, and another eight were used as part of test apparatus) were installed and tested for the site in Wellington, New Zealand. Of the three test piles, two were tested for tension, and one was tested for compression.
The piles were drilled during 4.5m and 12.5m below existing floor level with two type of drill head; 50mm cross cut drill head, and 550 button bit drill head. Of these three piles, one was typical drilling, one was partially cased with PVC pipe with a 3 x 52/26 11m long Ischebeck tripod cage, and another one was partially cased with steel tube which internally to be filled with penetrated grout through pre-drilled holes on washer plate above grout body.
The objective of these tests was to determine the load capacity of piles for tension and compression by testing to failure, namely, test to grout body/ground failure. The target load was about 1500 KN, and up to 2800 KN if site condition allows. The outcome resulted in CCS proceeding with micropile installation works, which are ongoing.
Address: Taranaki St, Wellington
Scope of testing: Five tension tests, one compression test
Eight micropiles (five of them have been tested, and another three used as part of test apparatus) were installed both inside and outside of the existing building located at Taranaki Street, Wellington. One pile was installed inside the building and seven piles were installed outside of the building near the car park area. The pile inside the building was set up for tension test. For the rest of the four test piles outside of the building, Two were used only for tension test, and two were set up for both tension test and compression test (only one pile was tested for both tension and compression as the other pile failed in tension).
The objective of these tests is to determine the load capacity of piles for tension and compression by testing to failure, namely, test to grout/ground failure or up to yield strength of the tendon during tension tests, and test to grout/ground failure or up to two times the tendon’s yield strength during compression tests. Such tests are known as investigation test.
The outcome has resulted in CCS proceeding with micro pile installation works, which have since been successfully completed to a high standard.